Method for sterilizing a lumen device

ABSTRACT

A method and an apparatus for sterilizing a lumen device. A lumen and a container having an interface on a wall of the container are enclosed in a chamber. The lumen is placed across the interface so that one end of the lumen is in the container and the other end is in the chamber. Germicide is introduced into the chamber, and a pressure difference is created between the two ends of the lumen, so that the germicide flows through the lumen. The lumen may alternatively be placed across an interface which separates the chamber into two areas. Germicide is introduced into the chamber, and a pressure difference is created between the two areas of the chamber, causing the germicide to flow through the lumen.

RELATED APPLICATIONS

This application is a division of application Ser. No. 09/802,326 filedMar. 8, 2001 now U.S. Pat. No. 6,977,061, which is a continuation-inpart of application Ser. No. 09/323,610, filed Jun. 1, 1999, now U.S.Pat. No. 6,528,015, which is a continuation of application Ser. No.08/915,922, filed Aug. 21, 1997, now U.S. Pat. No. 6,066,294;application Ser. No. 09/802,326 is also a continuation-in part ofapplication Ser. No. 09/643,336, filed Aug. 22, 2000, now U.S. Pat. No.6,319,480, which is a continuation of application Ser. No. 09/105,491,filed Jun. 26, 1998, now U.S. Pat. No. 6,174,502, which is a divisionalof application Ser. No. 08/833,375, filed Apr. 4, 1997, now U.S. Pat.No. 5,961,921.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to systems and methods for chemical sterilizationof medical devices with lumens, and more particularly to systems with acontainer having an interface.

2. Description of the Related Art

Medical instruments have traditionally been sterilized using eitherheat, such as is provided by steam, or a chemical, in the gas or vaporstate. Sterilization using hydrogen peroxide vapor has been shown tohave some advantages over other chemical sterilization processes.

The combination of hydrogen peroxide with a plasma provides certainadditional advantages, as disclosed in U.S. Pat. No. 4,643,876, issuedFeb. 17, 1987 to Jacobs et al. U.S. Pat. No. 4,756,882, issued Jul. 12,1988 also to Jacobs et al. discloses the use of hydrogen peroxide vapor,generated from an aqueous solution of hydrogen peroxide, as a precursorof the reactive species generated by a plasma generator. The combinationof hydrogen peroxide vapor diffusing into close proximity with thearticle to be sterilized and plasma acts to sterilize the articles andremove residual hydrogen peroxide. However, effective sterilization ofarticles having long narrow lumens are very difficult to achieve, sincethe methods are dependent upon diffusion of the sterilant vapor intoclose proximity with the article before sterilization can be achieved.Thus, these methods have been found to require high concentration ofsterilant, extended exposure time and/or elevated temperatures when usedon long, narrow lumens. For example, lumens longer than 27 cm and/orhaving an internal diameter of less than 0.3 cm have been particularlydifficult to sterilize. The sterilization of articles containing longnarrow lumens therefore presents a special challenge.

U.S. Pat. No. 4,744,951 to Cummings et al. discloses a two-chamberedsystem which provides hydrogen peroxide in vapor form for use insterilization processes. The sterilant is initially vaporized in onechamber and then applied to the object to be sanitized in another singlesterilizing chamber, thereby producing a concentrated hydrogen peroxidevapor which is relatively more effective. The sterilization processesare designed for furnishing concentrated hydrogen peroxide vapor tointerior surfaces of articles having a tortuous or a narrow path.However, the sterilization processes are ineffective at rapidlysterilizing lumened devices, since they depend on the diffusion of thehydrogen peroxide vapor into the lumen to effect sterilization.

U.S. Pat. No. 4,797,255 to Hatanaka et al. discloses a two-chamberedsterilization and filling system consisting of a single sterilizationchamber adjacent to a germ-free chamber utilized for drying and fillingsterilized containers.

U.S. Pat. No. 4,863,688 to Schmidt et al. discloses a sterilizationsystem consisting of a liquid hydrogen peroxide vaporization chamber andan enclosure for sterilization. The enclosure additionally may holdcontainers wherein the hydrogen peroxide sterilant vapor does notcontact the interior of the containers. This system is designed forcontrolling the exposure to the hydrogen peroxide vapor. The system isnot designed for sterilizing a lumen device.

U.S. Pat. No. 4,952,370 to Cummings et al. discloses a sterilizationprocess wherein aqueous hydrogen peroxide vapor is first condensed onthe article to be sterilized, and then a source of vacuum is applied tothe sterilization chamber to evaporate the water and hydrogen peroxidefrom the article. This method is suitable to sterilize surfaces,however, it is ineffective at rapidly sterilizing lumened devices, sinceit too depends on the diffusion of the hydrogen peroxide vapor into thelumen to effect sterilization.

U.S. Pat. No. 4,943,414, entitled “Method for Vapor Sterilization ofArticles Having Lumens,” and issued to Jacobs et al., discloses aprocess in which a vessel containing a small amount of a vaporizableliquid sterilant solution is attached to a lumen, and the sterilantvaporizes and flows directly into the lumen of the article as thepressure is reduced during the sterilization cycle. This system has theadvantage that the water and hydrogen peroxide vapor are pulled throughthe lumen by the pressure differential that exists, increasing thesterilization rate for lumens, but it has the disadvantage that thevessel needs to be attached to each lumen to be sterilized.

U.S. Pat. Nos. 4,937,046, 5,118,471 and 5,227,132 to Anderson et al.each disclose a sterilization system which uses ethylene oxide gas forsanitation purposes. The gas is initially in a small first enclosure andthereafter slowly permeates into a second enclosure where the objects tobe sterilized are located. A medium is then introduced into the secondenclosure to flush out the sterilizing gas into a third enclosurecontaining the second enclosure. An exhaust system then exhausts thesterilant gas and air from the third enclosure. These systems also havethe disadvantage of relying on the diffusion of the sterilant vapor toeffect sterilization and hence are not suitable for rapidly sterilizinglumened devices.

U.S. Pat. No. 5,122,344 to Schmoegner discloses a chemical sterilizersystem for sterilizing items by vaporizing a liquid chemical sterilantin a sterilizing chamber. Pre-evacuation of the sterilizer chamberenhances the sterilizing activity. Sterilant is injected into thesterilizer chamber from a second prefilled shot chamber. This systemalso relies upon diffusion of sterilant vapor to effect sterilizationand is also not suitable for rapidly sterilizing lumened devices.

U.S. Pat. No. 5,266,275 to Faddis discloses a sterilization system fordisinfecting instruments. The sterilization system contains a primarysterilization chamber and a secondary safety chamber. The secondarysafety chamber provides for sensing and venting to a destruction chamberany sterilization agent that is released from the primary sterilizationchamber. This system, as in other systems, also relies upon diffusion ofsterilant vapor to effect sterilization and is also not suitable forrapidly sterilizing lumened devices.

In U.S. Pat. Nos. 5,492,672 and 5,556,607 to Childers et al, there isdisclosed a process and apparatus respectively for sterilizing narrowlumens. This process and apparatus uses a multicomponent sterilant vaporand requires successive alternating periods of flow of sterilant vaporand discontinuance of such flow. A complex apparatus is used toaccomplish the method. Additionally, the process and apparatus of ′672and ′607 require maintaining the pressure in the sterilization chamberat a predetermined subatmospheric pressure.

In U.S. Pat. No. 5,527,508 to Childers et al., a method of enhancing thepenetration of low vapor pressure chemical vapor sterilants into theapertures and openings of complex objects is disclosed. The methodrepeatedly introduces air or an inert gas into the closed sterilizationchamber in an amount effective to raise the pressure to a subatmosphericpressure to drive the diffused sterilant vapor further into the articleto achieve sterilization. The ′508, ′672 and ′607 Childers inventionsare similar in that all three require repeated pulsations of sterilantvapor flow and maintenance of the sterilization chamber pressure at apredetermined subatmospheric pressure.

In U.S. Pat. No. 5,534,221 to Hillebrenner et al., a device and methodfor sterilizing and storing an endoscope or other lumened medical deviceis disclosed. The device includes a sealable cassette in which theendoscope or other medical device is placed. The cassette has an inputport for receiving a sterilizing agent through a connector, an outputport for expelling the sterilizing agent when a vacuum is appliedthereto through a connector, and check valves in the input and outputports to open the ports when the connectors are coupled to the ports andto seal the ports when the connectors are removed from the ports suchthat after the endoscope has been sterilized, it remains sterilizedwithin the cassette until the cassette is opened. The method of the ′221invention involves placing the medical device inside the cassette andcoupling the device to either the input or output port of the cassette.The cassette is then placed in an outer oven-like container or warmingchamber where the temperature is properly maintained. Connections aremade to open the input and output ports on the cassette such that thesterilizing agent may be introduced through a first port to bathe theoutside of the medical instrument or other object, such as an endoscopewhile one end of the hollow object, such as the endoscope, is coupled tothe output port where a vacuum is supplied external to the cassette topull the sterilization agent into the cassette and through the interiorpassageways of the endoscope. When the sterilization process iscompleted, the warming chamber is opened and the sterilizing cassette issimply removed from the chamber with the input and output ports beinguncoupled from their respective sources. A tight seal is maintained andthe object remains in the sterilized interior of the cassette until thecassette is opened or the device is to be used. Thus, the ′221 inventionis concerned with providing a means whereby a sterilized medical devicecan be retained within a cassette in which it was sterilized until readyfor use, thus avoiding any contamination by exposure to the atmosphereor handling before use. Additionally, in some cases of the ′221invention, wherein the lumen of the device to be sterilized is connectedto the output port, particularly wherein the devices have long, narrowlumens, the time to expel the sterilizing agent through the lumen andout of the cassette may be undesirably long. Also, in cases wherein thelumen device is very flexible, lumen collapse may occur, either slowingor preventing vapor exit or causing lumen damage.

U.S. Pat. Nos. 5,445,792 and 5,508,009 to Rickloff et al. each disclosea sterilization system essentially equivalent to the system disclosed inHillebrenner ′221.

U.S. Pat. No. 5,443,801 to Langford teaches a transportablecleaning/sterilizing apparatus and a method for inside-outsidesterilization of medical/dental instruments. The apparatus avoids theuse of heat, pressure, severe agitation, or corrosive chemicals whichmight damage delicate equipment. This invention uses ozone gas orsolution as sterilant. It does not involve the use of sterilant vapor orvaporizing a sterilant solution into vapor, and is not suitable foroperations under vacuum because flexible bags or containers are used.

In consideration of the foregoing, no simple, safe, effective method ofsterilizing smaller lumens exists in the prior art. Thus, there remainsa need for a simple and effective method of vapor sterilization ofarticles with both long, narrow lumens as well as shorter, wider lumens.Furthermore, there also remains a need for a simple and effectivesterilization system with independently operable chambers.

SUMMARY OF THE INVENTION

One aspect of the invention involves a method for enhancing thesterilization of a lumen, where the lumen has at least a first end and asecond end. The method includes enclosing the lumen and a container in achamber, where the container has at least one interface on a wall of thecontainer, and where the container does not contain germicide. The lumenis placed across the interface such that one end of the lumen is in thecontainer and the other end of the lumen is in the chamber. The methodalso includes introducing a germicide into the chamber, creating ahigher pressure in the chamber than in the container, and flowing thegermicide from the chamber into the container through the lumen.

Advantageously, the chamber is evacuated before the germicide isintroduced into the chamber. Preferably, the chamber is evacuated afterthe germicide flows from the chamber into the container through thelumen. In an embodiment, the chamber is vented after the germicide flowsfrom the chamber into the container through the lumen. Preferably, thegermicide includes hydrogen peroxide. Advantageously, the interfaceincludes at least one opening. In an embodiment, the opening includes amaterial which is permeable to the germicide, whereby the contact areabetween the interface and the lumen is contacted with the germicide. Themethod may also include adjusting the opening. Preferably, the containeris evacuated through a communication port in the container, where thecommunication port is different from the opening.

Another aspect of the invention involves a system for sterilizing alumen, where the lumen has at least a first end and a second end. Thesystem includes a container with at least one interface on a wall of thecontainer, where the container does not contain germicide. The systemalso includes a chamber which contains the container. The lumen isplaced across the interface such that the first end of the lumen is inthe container and the second end of the lumen is in the chamber. Thesystem also includes at least one pump to evacuate the chamber and thecontainer and a source of germicide.

The source of germicide may be in the chamber or in an enclosure influid communication with the chamber. Preferably the source of germicideincludes hydrogen peroxide. Advantageously, the interface has at leastone opening. In an embodiment, the opening includes a material which ispermeable to germicide generated from the source of germicide, where thematerial is located at least in the contact area between the interfaceand the lumen. Preferably, the container also includes a communicationport in fluid communication with the pump, where the communication portis different from the opening. In an embodiment, the opening isadjustable.

Another aspect of the invention involves a system for sterilizing alumen device. The system includes a chamber having at least oneinterface, where the interface separates the chamber into a first areaand a second area. The system also includes a source of germicide and acontainer inside the chamber, where at least a portion of the containeris located in the first area of the chamber and a least a portion of thecontainer is located in the second area of the chamber. The containerincludes at least one interface, where the interface separates thecontainer into at least a first compartment and a second compartment.The container also includes at least one communication port, where thecommunication port provides fluid communication between the containerand the chamber. The container includes at least one lumen deviceextending across the interface in the container, whereby the firstcompartment is in fluid communication with the second compartmentthrough the lumen device.

Preferably, the interface includes at least one opening. Advantageously,the opening is adjustable. In an embodiment, the opening includes amaterial which is permeable to germicide generated from the source ofgermicide, where the material is located at least in the contact areabetween the interface and the lumen. Preferably, the system alsoincludes at least one vacuum pump to evacuate the chamber and/or thecontainer. Advantageously, the source of germicide includes hydrogenperoxide. In an embodiment, the communication port includes a gas orvapor permeable membrane. Preferably, the gas or vapor permeablemembrane is impermeable to microorganisms. In an embodiment, at leastone communication port provides fluid communication between the firstcompartment and the chamber and at least one communication port providesfluid communication between the second compartment and the chamber.

Yet another aspect of the invention involves a method for sterilizing alumen device The method includes enclosing a container in a chamber,where the container includes an interface, where the interface separatesthe container into a first compartment and a second compartment. Thecontainer also includes at least one lumen device extending across theinterface, whereby said the first compartment is in fluid communicationwith the second compartment through the lumen device. The container alsoincludes at least one communication port in the container, where thecommunication port provides fluid communication between the containerand the chamber. The method includes providing a germicide in at leastone of the chamber, the container, and an enclosure in fluidcommunication with the chamber. A pressure difference is created betweenthe chamber and the container, creating a pressure difference betweenthe first compartment and the second compartment. The germicide flowsbetween the chamber and the container through the communication port inthe container and between the first compartment and the secondcompartment through the lumen device.

Advantageously, the germicide includes hydrogen peroxide. Preferably,the method also includes removing the container from the chamber. In anembodiment, the sterility of the lumen device is maintained in thecontainer. Preferably, the interface includes at least one opening.Advantageously, the opening includes a material which is permeable tothe germicide, whereby the contact area between the interface and thelumen is contacted with the germicide. The method may also includeadjusting the opening.

Another aspect of the invention involves a system for sterilizing alumen device in a chamber, where the system includes a vacuum chamber,an interface, where the interface separates the vacuum chamber into afirst compartment and a second compartment, and at least one lumendevice extending across the interface, whereby the first compartment isin fluid communication with the second compartment through the lumendevice. The system also includes a source of germicide and at least onevacuum pump.

Advantageously, the interface includes at least one opening. Preferably,the opening is adjustable. In an embodiment, the opening includes amaterial which is permeable to germicide generated from the source ofgermicide, where the material is located at least in the contact areabetween the interface and the lumen. Advantageously, a germicide vaporor gas is generated from the source of germicide. Preferably, the sourceof germicide includes hydrogen peroxide.

Another aspect of the invention involves a method for sterilizing alumen device in a vacuum chamber. The method includes separating thevacuum chamber into a first compartment and a second compartment with aninterface, where at least one lumen device extends across the interface,whereby the first compartment is in fluid communication with the secondcompartment through the lumen device. The method also includesevacuating the vacuum chamber, thereby decreasing the pressure in thefirst compartment and the second compartment. The method also includesintroducing germicide into at least one of the first compartment and thesecond compartment, where introducing occurs after evacuating, andcreating a pressure difference between the first compartment and thesecond compartment, thereby flowing germicide between the firstcompartment and the second compartment through the lumen device.

Advantageously, the germicide includes hydrogen peroxide. Preferably,the interface includes at least one opening. In an embodiment, theopening includes a material which is permeable to the germicide, wherebythe contact area between said interface and said lumen is contacted withgermicide. The method may also include adjusting the opening.Advantageously, the method also includes increasing the pressure in thefirst compartment and the second compartment, where the pressure isincreased after the germicide is introduced and after a pressuredifference is created between the first compartment and the secondcompartment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic diagram of an embodiment of the apparatus of thepresent invention showing two chambers separated with a sealableinterface;

FIG. 1B is a schematic diagram of an embodiment of the apparatus of thepresent invention showing the interface, doors and two chambers;

FIG. 2 is a schematic diagram of an embodiment of the apparatus of thepresent invention showing two chambers separated by an interface and influid communication through a lumen device;

FIG. 3 is a schematic diagram of an embodiment of the apparatus of thepresent invention showing one chamber placed in another chamber;

FIG. 4 is a schematic diagram of an embodiment of the apparatus of thepresent invention showing one chamber in another with lumen connectingthe two chambers;

FIG. 5 is a schematic diagram of an embodiment of the apparatus of thepresent invention showing two chambers containing containers;

FIG. 6A is a schematic diagram of an embodiment of the apparatus of thepresent invention showing two chambers containing containers and beingconnected through a lumen;

FIG. 6B is a cross sectional view of the system of FIG. 6A;

FIG. 7 is a schematic diagram of an embodiment of the apparatus of thepresent invention showing a container in the chambers separated with aninterface.

FIG. 8 is a schematic diagram of an alternative embodiment of theapparatus of FIG. 2, showing two compartments separated by an interfaceand in fluid communication through a lumen device;

FIG. 9 is a schematic diagram of an alternative embodiment of theapparatus of FIG. 6A, showing a lumen in a container, where thecontainer is placed into an interface between two chambers.

FIG. 10 is a schematic diagram of an alternative embodiment of theapparatus of FIG. 4, showing one chamber in another with a lumenconnecting the two chambers; and

FIG. 11 is a schematic diagram of an alternative embodiment of theapparatus of FIG. 4, showing one chamber in another with a lumenconnecting the two chambers.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The multi-compartment sterilization apparatus of the present inventionis suitable for the sterilization of both non-lumen and lumen devices.

According to one aspect of the present invention, the multi-compartmentsterilization apparatus comprises at least two chambers separated by asealable and removable interface. Each of the chambers can be operatedindependently and serve as a sterilization chamber. In a sterilizationprocess using the apparatus of the present invention, the interface canbe adjusted for different situations. For example, if the device to besterilized is too big to fit into either one of the two chambers, theinterface can be removed so that more space will be available toaccommodate the device. If the device is not so big, it can besterilized in one of the two chambers while other devices can beprepared for sterilization in the other chamber.

According to another aspect of the present invention, themulti-compartment sterilization apparatus comprises a sterilizationsystem with a multi-chambered compartment having at least a first rigidchamber and a second rigid chamber, an openable and closeable interfacebetween the first and second chamber, a flow path between the first andsecond chamber, and a source of sterilant adapted to provide thesterilant in the first and/or second chamber. The flow path can be alumen of the device to be sterilized, so that sterilant can flowdirectly through the lumen to sterilize the interior of the lumendevice. Different sterilization methods and technologies can be used incorporation with the sterilization system of the present invention.Several embodiments of those methods are described below:

Method to Deliver a Predetermined Amount of Liquid Sterilant

Conventional sterilants can be used in the present invention. Numeroussterilants are available in the art, such as formaldehyde, ethyleneoxide, hydrogen peroxide solution and hydrogen peroxide vapor. Althoughany of those sterilants can be used in the sterilization apparatus ofthe present invention, the use of hydrogen peroxide solution andhydrogen peroxide vapor has been shown to have some advantages overother chemical sterilization processes. Therefore, it is preferred touse hydrogen peroxide solution and hydrogen peroxide vapor as sterilantin the present invention. In a sterilization process using hydrogenperoxide solution as sterilant, the sterilant can be applied in severaldifferent ways. For example, a hydrogen peroxide solution can be firstvaporized under vacuum and/or heat in a vacuum chamber, and the deviceto be sterilized is then exposed to the hydrogen peroxide vapor.Accordingly, in one embodiment of the present invention, an importantparameter of the process needed to achieve satisfactory sterilization isthe amount of liquid hydrogen peroxide entering into the chamber to bevaporized. Thus, it is important that the liquid hydrogen peroxide bedelivered to the chamber in measured quantities.

A sterilization apparatus able to deliver a predetermined amount ofliquid sterilant can be incorporated into the sterilization system ofthe present invention. Thus, the sterilization chamber may have a bottomwall with at least one well which defines a known volume. The well ispositioned so that when a liquid sterilant is introduced onto the bottomsurface, a known volume of the liquid sterilant fills the well and whenthe liquid sterilant is drained from the surface, the known volume ofliquid sterilant remains in the well so that a subsequent sterilizationprocess can be performed on the device positioned on the bottom surfacewith the known volume of liquid sterilant positioned within the bottomsurface. The apparatus may also include a heat source and/or a vacuumsource for vaporizing the liquid sterilant in the well, and canoptionally include a source of plasma. The bottom surface preferably hasat least one perforation for draining the liquid sterilant from thebottom surface. The well formed in the bottom surface can be curved,flat or angled. Thus, the well can be an inwardly extendinghemispherical projection. The well can also be formed in the bottomsurface as an inwardly extending rectangular projection having roundedends. The well formed in the bottom surface can also be a rectangularbox having side walls, defining an opening. Where perforations areprovided, they can be disposed adjacent the well, and can be roughlyspherical in shape. The upwardly extending projection can include aperforation thereon, which can be on top of the projection or on a sideof the projection. The bottom surface can be a sloped surface, a convexor concave surface or a V-shaped surface. The bottom surface can be of avariety of materials including stainless steels, aluminum, aluminumalloys, liquid crystal polymers, polyesters, polyolefin polymers orfluorinated polyolefins. If the bottom surface is comprised of acomposite material, the composite material can include a filler of highthermal conductivity. Examples of composite materials include ametal-filled polymer, a ceramic-filled polymer and a glass-filledpolymer. Those materials are also suitable for the side walls and doorsof the sterilization chamber.

Method Based on Diffusion Restricted Environments

A method of hydrogen peroxide vapor sterilization ofdiffusion-restricted environments can also be used in corporation withthe present invention. In this embodiment of the present invention, thedevices (lumen or non-lumen) to be sterilized are pretreated with ahydrogen peroxide solution, and then exposed to pressures less than thevapor pressure of sterilant. The inside of lumens is sterilized bytaking advantage of the diffusion-restricted environments within thelumens.

As used herein, a “diffusion-restricted” area refers to any one or moreof the following properties: (1) the ability of the area of an articleplaced within the sterilization system of the present invention toretain 0.17 mg/L or more hydrogen peroxide solution after one hour at40° C. and 10 torr; (2) having the same or more diffusion restrictionthan provided by a single entry/exit port of 9 mm or less in internaldiameter and 1 cm or greater in length; (3) having the same or morediffusion restriction than provided by a lumen 27 cm in length andhaving an internal diameter of 3 mm; (4) having the same or morediffusion restriction than provided by a lumen having a ratio of lengthto internal diameter greater than 50; (5) the ability of an articleplaced within the sterilization system of the present invention toretain 17% or more of the hydrogen peroxide solution placed thereinafter one hour at 40° C. and 10 torr; or (6) being sufficientlydiffusion-restricted to completely sterilize a stainless steel bladewithin a 2.2 cm by 60 cm glass tube having a rubber stopper with a 1 mmby 50 cm stainless steel exit tube therein at a vacuum of 10 torr forone hour at 40° C. in accordance with the present invention. It isacknowledged that characteristics (1) and (5) will vary depending on theinitial concentration of hydrogen peroxide placed into the article;however, this can be readily determined by one having ordinary skill inthe art.

In this embodiment of the present invention, a method for sterilizing aninterior of a device with a diffusion restricted area, such as a devicehaving a lumen, is used in corporation with the sterilization system.The method includes the steps of contacting the interior of the devicewith a liquid solution comprising hydrogen peroxide, and exposing thedevice to negative pressure for a time period sufficient to effectcomplete sterilization. In one embodiment, the liquid solution isperacetic acid. If the exposing step is conducted for 1 hour at 40° C.and 10 torr, the diffusion restricted area preferably retains 0.17 mg/Lor more hydrogen peroxide, or retains 17% or more of the hydrogenperoxide placed therein after the exposing step. In certain preferredembodiments, the diffusion-restricted area has the same or morediffusion restriction than provided by a lumen 27 cm in length and aninternal diameter of 3 mm, or has the same or more diffusion restrictionthan provided by a lumen having a ratio of length to internal diametergreater than 50. The solution is preferably at a concentration of lessthan 25% by weight. The contacting step can be performed by delivery viaa method such as injection, static soak, liquid flow-through or aerosolspray. In a preferred embodiment, the diffusion-restricted area is alumen at least 27 cm in length and having an internal diameter of nomore than 3 mm, more preferably having an internal diameter of no morethan 1 mm. The exposing step is preferably performed for 60 minutes orless, and is preferably performed at a pressure less than the vaporpressure of hydrogen peroxide. Thus, the preferred pressure range underconditions of the present invention is between 0 and 100 torr. In oneparticularly preferred embodiment, the pressure is approximately 10 torrand the exposing step is conducted at a temperature of approximately 23°C. to approximately 28° C. The exposing step can include the step ofheating the article, such as by heating the chamber in which theexposing step occurs. The chamber can be heated to about 30° C. to about45° C. Alternatively, the solution can be heated, such as to atemperature of about 30° C. to about 45° C. Optionally, the step ofexposing the device to a plasma can be conducted during the step ofexposing the device to negative pressure. In one embodiment employingexposure to plasma, the method is performed within a first chamber andthe plasma is generated in a second, separate chamber. This embodimentfurther comprises the step of flowing the plasma into the first chamber.Advantageously, the contacting and/or exposing steps of the method canbe repeated one or more times.

Sterilization Methods in Non-diffusion Restricted Environments

The present invention can also be used to sterilize devices with lumenswithout relying on a diffusion-restricted environment.

It has been discovered by the inventors that similar sterilizationresults to those created in diffusion-restricted environments can becreated through controlling the evacuation rate of the chamber in whicharticles to be sterilized are placed. Thus, in one embodiment of thepresent invention, a method for sterilizing a device can be used incorporation with the sterilization system of the present invention. Themethod comprises the steps of contacting the device with liquidsterilant outside or inside a sterilization chamber at a first pressure;placing the device in the chamber before or after the contacting step;and decreasing the pressure of the chamber to a second pressure belowthe vapor pressure of the liquid sterilant in which at least a portionof the decrease in pressure below about the vapor pressure of the liquidsterilant occurs at a pumpdown rate of less than 0.8 liters per second,calculated based on the time required to evacuate the chamber fromatmospheric pressure to 20 torr when the chamber is empty and dry, i.e.when the chamber has neither articles to be sterilized nor a visiblequantity of liquid within it. According to one aspect of this preferredembodiment, at least the decrease in pressure below about two times thevapor pressure of the liquid sterilant occurs at a pumpdown rate of lessthan 0.8 liters per second. According to another aspect of thisembodiment, the decrease in pressure below about four times the vaporpressure of the liquid sterilant occurs at a pumpdown rate of less than0.8 liters per second. Preferably, the pumpdown rate is 0.6 liters persecond or less; more preferably, 0.4 liters per second or less; and mostpreferably, 0.2 liters per second or less. Advantageously, the firstpressure is atmospheric pressure. Preferably, the liquid sterilant ishydrogen peroxide. In another aspect, the device is a medical instrumenthaving a lumen.

The present invention can also use a method for sterilizing a devicecomprising the steps of (a) contacting the device with liquid sterilantoutside or inside a sterilization chamber at a first pressure; (b)placing the device in the chamber before or after the contacting step;(c) pumping down the chamber to a second pressure which is lower thanthe first pressure at a first rate; and (d) pumping down the chamber toa third pressure which is lower than the second pressure, wherein atleast a portion of the pumping down to the third pressure is at a secondrate which is slower than the first rate. The pumpdown rate either aboveand/or below the second pressure can be constant or variable. In certainembodiments, the pumpdown rate either above and/or below the secondpressure is reduced in stepwise fashion. Preferably, the second pressureis greater than or equal to about the vapor pressure of the liquidsterilant; more preferably, the second pressure is greater than or equalto about two times the vapor pressure of the liquid sterilant; mostpreferably, the second pressure is greater than or equal to about fourtimes the vapor pressure of the liquid sterilant. Advantageously, thepumpdown rate in step (d) is 0.8 liters/sec or less; more advantageously0.6 liters/sec or less; even more advantageously 0.4 liters/sec or less;and most advantageously 0.2 liters/sec or less, calculated based on thetime required to evaluate the chamber from atmospheric pressure to 20torr under empty and dry conditions. Preferably, the liquid sterilant ishydrogen peroxide. In another aspect of this embodiment, the device is amedical instrument having a lumen. Preferably, the pumping down of step(c) reduces the pressure to less than about three times, more preferablyto less than about two times, the vapor pressure of the liquidsterilant.

Another suitable method includes contacting the article with liquidsterilant either inside or outside of the sterilization chamber, placingthe device in the chamber either before or after the contacting step,and reducing the pressure of the chamber while regulating the pumpdownrate so as to control the evaporation rate of sterilant in said chamber.In any of the methods described above, the contacting step may compriseapplication of liquid or condensed vapor. These methods described abovemay additionally comprise further evacuating the chamber to removeresidual sterilant. Further, these methods described above mayadditionally comprise exposing the device to plasma to remove residualsterilant or enhance sterilization efficacy. The contacting step inthese methods can be either by direct or indirect contacting. As statedhereinbelow, indirect contacting involves introducing sterilant into thechamber without directly contacting the article to be sterilized.

In another embodiment, a two step pump down sterilization process can beused in connection with the sterilization system of the presentinvention. The method comprises the steps of: contacting a device withliquid sterilant outside or inside a sterilization chamber, placing thedevice in the chamber before or after the contacting step; bringing thepressure of the chamber to a first pressure range at which liquidsterilant is vaporized from the non-diffusion restricted area tosterilize the non-diffusion restricted area; bringing the pressure ofthe chamber to a second pressure range at which the liquid sterilant isvaporized from the diffusion restricted area to sterilize the diffusionrestricted area, wherein the minimum pressure in the second pressurerange is lower than the maximum pressure in the first pressure range.

Preferably, the first pressure range is 20 to 760 torr; more preferably,the first pressure range is 20 to 80 torr; most preferably, the firstpressure range is 40-50 torr. Advantageously, the second pressure rangeis 1-30 torr; more advantageously, the second pressure range is 5-10torr. In one aspect of this preferred embodiment, the device includes adiffusion-restricted environment. Preferably, the device is a medicalinstrument with a lumen having an interior and an exterior surface.Advantageously, the sterilant is hydrogen peroxide. According to anotheraspect of this preferred embodiment, the chamber is at a set temperatureand wherein the first pressure is greater than the vapor pressure of thesterilant at the set temperature. Preferably, the pressure of thechamber is maintained constant at the first pressure for a time periodsufficient to sterilize the non-diffusion restricted area.Advantageously, the pressure of the chamber is maintained constant atthe second pressure for a time period sufficient to sterilize thediffusion restricted area. The pressure of the chamber may be permittedto increase after reaching the first or second pressure range as aresult of vaporization of the sterilant within said chamber.Alternatively, the pressure of the chamber is permitted to decreaseafter reaching the first or second pressure through pumping of saidchamber at a rate slower than used to decrease the pressure between saidfirst and second pressure ranges. Preferably, the contacting step iswith liquid or condensed vapor. The method can also include the steps ofbringing the pressure to a third pressure lower then the second pressureto remove residual sterilant and/or exposing the device to plasma toremove residual sterilant or enhance sterilization efficacy.

Method Involving Direct Flow Through a Lumen of Devices to be Sterilized

According to the present invention, a sterilization apparatus isprovided which can more efficiently sterilize devices with long narrowlumens by flowing a sterilant, either in liquid phase or in vapor phase,directly through the lumens of lumen devices to be sterilized.

The flow of a sterilant (solution or vapor) through a lumen of a medicaldevice is realized by a pressure drop between two ends of the lumen. Thepressure drop can be generated by applying either a vacuum or a highpressure at one end. By generating a forced flow through a pressuredifferential other than relying on diffusion, the sterilization rate issignificantly increased and less time is needed for a sterilizationcycle.

It is clear from the above discussion that the two ends of the lumenneed to be exposed to a pressure differential. This is achieved in thepresent invention by placing a sealable interface between the twochambers. An opening is provided in the interface and the lumen deviceto be sterilized is placed through the opening in such a way that thelumen serves as a flow path between the two chambers.

The opening can be constructed in several ways. One way to achieve thisis with a camera shutter approach employing an iris diaphragm, such as aprecision iris diaphragm from Edmund Scientific. An optional spring canbe used to secure the closure of the shutter. Another way to achieve anacceptable opening is to employ two plates, wherein the area between thetwo plates has a compressible material, such as a rubber material. Thelumen device can be placed between the two plates and the two platesmoved together to form a gas and vapor impermeable seal around the lumendevice. Optionally, a porous material like a sponge or air permeablematerial may be utilized for the compressible material. In this casesome sterilant can flow between the compressible material and the lumendevice. However, most the sterilant flows through the lumen device. Yetanother acceptable interface is a hole or horizontal opening for one ormore lumen devices, said hole or opening being a gas or liquidinflatable so that by inflating the inflatable material on the hole oropening the lumen devices are held and sealed. Still another option isto place a compressible material on top of an inflatable material so asto facilitate the sealing around the lumen device.

The closing and opening movement of the opening such as the plate andthe iris diaphragm can be controlled mechanically or electronically withany conventional mechanism.

It is sealed to a different degree between the opening and the lumendevice depending on the desired purpose. For example, the opening canform a gas-tight seal around the lumen device so that nothing can flowoutside of the lumen device through the opening; or form a loose-fittingseal around the lumen device allowing sterilant to flow outside of thelumen device through the opening so that the exterior of the lumendevice adjacent the opening can be sterilized; or form a tight-fittingwith a porous material, such as a gas and/or liquid permeable membranearound the lumen device so that gas and sterilant can pass and, in themeantime, the porous material helps to hold the lumen device. Theinterface can be made openable, closeable, and removable. A flow pathbetween different chambers can be also provided outside thesterilization system.

In order to promote sterilization efficiency, all the sterilizationapparatus of the present invention can be further equipped with aheater, vacuum, and/or a plasma.

The present invention is further described in connection with thedrawings below. In the following figures like numbers refer to likeparts throughout. Referring to FIG. 1A, the sterilization apparatuscomprises a first chamber 2 and a second chamber 4. The two chambers areseparated by a sealable and removable interface 6 so that the twochambers can be operated independently, i.e. different items can besterilized simultaneously in the two chambers, or one chamber isoperated for sterilization while the other is not in operation. Anenclosure 10 for receiving a sterilant source 12 is connected to each ofchambers 4 and 2 through a valve 14 a and a valve 14 b, respectively.Two enclosures 10 are shown in FIG. 1A. However, these two enclosures 10can be combined into one. Enclosure 10 can be made of materials similarto those of the walls of chambers 2 and 4. The sterilant source 12 canbe located in one or more locations of enclosure 10, chamber 2, and/orchamber 4. There are several way to control the amount of sterilantentering chamber 2 or 4 if such control is desired. For example, valves14 a and 14 b can be a metering valve and the amount of sterilantflowing from enclosure 10 to chambers 2 and 4 is measured and controlledby valve 14 a or 14 b; or enclosure 10 is equipped with a volume readingso that the volume of the sterilant in enclosure 10 can be read; orsterilant containing wells (not shown) can be provided in the chambersto control the amount of liquid sterilant. The sterilant source 12 canbe also located in chamber 2 and/or chamber 4.

Chambers 2 and 4 are equipped with a vacuum pump 16 for generatingvacuum within these chambers during the sterilization process. Valve 15a and valve 15 b are provided connecting vacuum pump 16 to chamber 4 and2, respectively. They are controlled independently. Chambers 2 and 4 canalso be equipped with a pump 18 to circulate sterilant between the twochambers. Chambers 2 and 4 can be of any desired shape, but a regularshape such as cylindrical or rectangular will make it easier toaccommodate the interface 6.

FIG. 1B shows more details of chambers 2 and 4 with interface and doors.As shown in this figure, chambers 2 and 4 can be equipped with doors 8a, 8 b, 9 a, and 9 b, respectively. One chamber does not necessarilyhave more than one door. There are a frame 11 a and a guiding piece 11 bbetween the two chambers. Interface 6 a or 6 b is secured between thetwo chambers through frame 11 a and guiding piece 11 b by sliding theinterface into gap 13 defined by frame 11 a and guiding piece 11 b. Ifnecessary, interface 6 a or 6 b can be further secured to frame 11 a byany conventional means, such as screw or clamp. A sealing O-ring (notshown) can be provided around the frame 11 a to generate a good sealingbetween the two chambers. The interface 6 a has an opening 7 adapted toreceive a lumen device. Opening 7 may have different shape and size toaccommodate different types of lumen devices. Under different situation,different interface can be chosen. The opening 7 is controllable. In oneembodiment the opening has a shutter structure which is electricallycontrolled. By changing the dimension of the opening, different degreeof seal between the opening and the lumen device held by the opening canbe achieved.

FIG. 2 shows a sterilization apparatus able to generate a sterilant flowthrough a lumen to be sterilized. As shown in FIG. 2, the apparatuscomprises a first chamber 2 and a second chamber 4. The two chambers areseparated by an openable and closeable interface 6 a. Interface 6 a hasan opening 7. A lumen device 40 with a lumen 42 is placed through theopening 7 in such a way that one end of the lumen 42 is in chamber 2 andthe other end in chamber 4. At least during a part of a sterilizationprocess for sterilizing the interior of the lumen 42, the opening 7 isgas-tight sealed around the lumen device 40 so that sterilant fluidflows through the lumen 42 under a pressure drop between the twochambers 2 and 4. Although a liquid sterilant can be used in theapparatus, sterilant vapor is preferred. The sterilant vapor can begenerated with any appropriate method known to the art or with themethod described in the copending application referenced previously.Generally speaking, the usual way to generate vapors in a sterilizationsystem is the use of heating and/or vacuum. In the present invention,both heating and vacuum can be employed to generate sterilant vapor.

In order to generate a flow of sterilant fluid through the lumen 42,pressure differential has to be exist between the two ends of the lumen42. One way of generating such a pressure gradient is to pressurize oneend of the lumen 42. But it is more desirable to apply vacuum to one endof the lumen 42 with vacuum pump 16, especially when sterilant vapor isused. The two chambers can be operated either under vacuum or underpressure up to about 4 atmospheres. The temperature of the two chamberscan be controlled independently through a conventional heating device(not shown). The operation temperature of the chambers are adjusted soas not to damage the device to sterilized. It is usually below 80° C.,more preferably 20-55° C.

Vacuum pump 16 is used to generate vacuum in either chamber 2 or chamber4 through valve 15 b and 15 a. Pump 18 is used to circulate sterilantbetween chamber 2 and chamber 4. If necessary, vacuum pump 16 and airpump 18 can be operated either simultaneously or sequentially.

In addition to lumen device 40, a plurality of devices can be sterilizedin both chamber 2 and 4. In this embodiment, the devices to besterilized can be pretreated or not pretreated with liquid sterilant.Because sterilant is circulated through the lumen 42, the interior ofthe lumen device 40 is mainly sterilized by the sterilant flowtherethrough. This direct circulation of sterilant provides an efficientsterilization of the interior of the lumen 42, especially, when hydrogenperoxide vapor is circulated through the lumen 42. Doors can be providedfor the two chambers at any convenient locations, for example, as shownin FIG. 1B. Sterilant can be provided from enclosure 10, or directlyfrom the source of sterilant 12. The sterilant source 12 can be in theform injection, static soak, liquid flowthrough, or aerosol spray.Liquid sterilant may also be placed on the wells (not shown) on thebottom surface of the chambers and is vaporized during the sterilizationby applying vacuum and/or heating.

All the features and functions of the apparatus shown in FIG. 1A anddescribed previously are applicable to the apparatus shown in FIG. 2.

FIG. 3 shows a top view of the two chambers in another embodiment of thepresent invention. The apparatus comprises similar elements as thatshown in FIG. 2, but they are configured differently. Chamber 4 is nowlocated inside chamber 2. Chambers 2 and 4 are still separatelyconnected to vacuum pump 16, enclosure 10, and pump 18 as shown in FIG.3. Pump 18 usually is not needed when there is no sterilant flow betweenthe two chambers. The two chambers are still independently operable. Oneof the advantages of the arrangement is that devices with greater lengthsuch as device 44 can be accommodated in the space between chamber 2 andchamber 4.

Chambers 2 and 4 share the top surface and the bottom surface, and areequipped with two sealable doors. Chamber 2 has a large door on the topsurface and chamber 4 has a smaller door on the upper surface. Thesmaller door is in the large door, but the two doors can be operatedindependently.

FIG. 4 shows an apparatus of the present invention similar to that shownin FIG. 3. The difference between the two embodiments shown in FIG. 3and FIG. 4 is that in the apparatus of FIG. 4 chamber 2 and chamber 4are in fluid communication through a lumen device 40. Therefore, thisapparatus has all the advantages possessed by the apparatus of FIG. 3.In addition, it can be used to effectively sterilize devices with longnarrow lumens. In this case, a removable interface 6 a with an opening 7is provided to accommodate the lumen device 40. The interface 6 a can beinstalled in a similar way as discussed and shown in FIG. 1B. Valves 19a and 19 b can be provided between pump 18 and the chambers.

FIG. 5 demonstrates the use of a container 20 in the chambers 2 and 4.For certain devices the sterility needs to be maintained after thesterilization. A sterilant vapor-permeable and microorganism-impermeablecontainer is usually used to achieve the goal to keep the microorganismaway form the sterilized devices after the devices have been sterilized.As shown in FIG. 5, a container 20 is placed in either chamber 2 orchamber 4, or both. The rest of the system is the same as the apparatusshown in FIG. 1A. The container is provided with a membrane (not shown)which is sterilant vapor-permeable and microorganism-impermeable and canbe located at any convenient position on the wall of the container 20.The sterilant vapor-permeable and microorganism-impermeable membrane canbe made of any conventional material known the art such as TYVEK™nonwoven polyethylene fabric, nonwoven polypropylene such as SPUNGUARD™,or similar material. During a sterilization process, the sterilant vaporgenerated from a liquid sterilant in chamber 2 or 4 penetrates into thecontainer 20 through the membrane and sterilizes the device placedinside the container 20. The devices to be sterilized can also bepretreated with liquid sterilant and then the liquid sterilant containedor absorbed by the devices is vaporized under vacuum applied throughvacuum pump 16. Another option is to provide the container 20 withliquid sterilant before the sterilization process starts, then close asealable door of the container 20, and apply vacuum to the container 20to vaporized the liquid sterilant contained in the container 20. Whenthe sterilization cycle is complete, the container is removed from thechamber. Because of the microorganism-impermeable feature, the container20 can maintain the sterility of the device inside the container 20.This greatly reduces the chance of re-contamination during the handlingof the sterilized device.

FIG. 6A shows a sterilization apparatus similar to that of FIG. 5. Inthe apparatus shown in FIG. 6A, a container 22 for lumen device 40 isplaced across opening 7 b in the interface 6 c. The opening 7 b issealed around the outside of the container 22, for example, by an O-ringor other similar material mounted in the opening 7 b. Container 22 alsohas an interface 22 a with an opening 22 b as shown in FIG. 6B. Theopening 22 b is also sealed around the outer surface of the, lumendevice 40 so that no gas or vapor can flow therebetween when the seal isin gas-tight seal state. When desirable, the sealing between the outersurface of the lumen device 40 and the opening 22 b of the interface 22a of the container 22 can be released so that the outer surface of thelumen device 40 adjacent the sealing is sterilized. A sterilantvapor-permeable and gas-permeable, but microorganism-impermeablemembrane 24 is provided to both portions of the container 22 in chamber2 and 4. The membrane 24 can be located at any convenient position oncontainer 22, such as at both ends of the container 22. Throughmembranes 24 and lumen 42 of the lumen device 40, chamber 2 and chamber4 are placed in fluid communication. By applying vacuum to eitherchamber with vacuum pump 16, a pressure differential can be establishedand a flow of sterilant is generated between the two chambers. Thecontainer 22 serves to maintain the sterility of the lumen device 40placed therein following the sterilization.

FIG. 7 shows a sterilization apparatus which comprises a container 26.The container 26 is divided by an interface 6 d. Like interface 6 adescribed FIG. 2, interface 6 d is sealable and has an opening 7 c.Container 26 is accessible to sterilant source 12 or enclosure 10. Thegap between the inner surface of chambers 2 and 4 and the outer surfaceof the container 26 is gas-tight sealed so that no air or sterilantvapor can flow through the gap from chamber 2 to chamber 4 or viceversa. In the embodiment shown in FIG. 7, the sealing of the gap betweenthe inner surface of chambers 2 and 4 and the outer surface of thecontainer 26 is provided at the about same location where the interface6 d separates the container 26 into two portions. The two portions ofthe container 26 separated by the interface 6 d are in fluidcommunication through the lumen 42. The opening 7 c is sealed around theouter surface of the lumen device 40 in the same manner as described inthe section for the apparatus shown in FIG. 2. A sterilantvapor-permeable and gas-permeable, but microorganism-impermeablemembrane is provided at both portions of the container 26. Thus, apressure differential can be generated between the two chambers andbetween the two portions of the container 26 by means of vacuum pump 16and/or pump 18. The pressure difference between the two portions of thecontainer 26 forces sterilant fluid to flow through the lumen 42, andboth the interior and the exterior of the lumen device 40 and otherdevices in the container 26 are efficiently sterilized. The sterility ofthe devices in the container 26 is maintained following thesterilization.

FIG. 8 shows an apparatus similar to the apparatus shown in FIG. 2,except that only lumen device 40 is present in chambers 2 and 4. Lumendevice 40 is placed into opening 7 in interface 6 a between firstchamber 2 and second chamber 4 so that part of lumen device 40 is inchamber 2, and part of lumen device 40 is in chamber 4. In theembodiment of FIG. 8, chamber 4 can be evacuated directly by the vacuumpump 16, through chamber 2, or both directly and through chamber 2.Sterilant can be circulated between chamber 2 and chamber 4 by pump 18.

In the apparatus of FIG. 8, a source of sterilant 12 can be located inchamber 4, chamber 2, either or both of the enclosures 10, both chamber4 and chamber 2, or any combination thereof. The sterilant can be aliquid, vapor, or gas. In order to sterilize the interior of lumen 42, apressure differential is created between the two ends of the lumen 42.The pressure gradient can be generated by pressurizing one end of lumen42, for example, by introducing sterilant into either chamber 2 orchamber 4. If sterilant is introduced into chamber 4, the pressure inchamber 4 is higher than the pressure in chamber 2, and the sterilantflows from chamber 4 through lumen device 40 into chamber 2. Ifsterilant is introduced into chamber 2, the pressure in chamber 2 ishigher than the pressure in chamber 4, and the sterilant flows fromchamber 2 through the lumen device 40 into chamber 4. When sterilant isintroduced into chamber 2 or chamber 4, the pressure in both chamber 2and chamber 4 increases due to the introduction of sterilant andflowthrough of sterilant through lumen 42. In another embodiment, oneend of the lumen 42 can be pressurized by circulating sterilant betweenchamber 2 and chamber 4 with pump 18.

Sterilant can be introduced into both chamber 2 and chamber 4 as long asthere is a pressure difference between chamber 2 and chamber 4. In anembodiment, a pressure difference between chamber 2 and chamber 4 can becreated by introducing sterilant into chamber 2 at a different rate thanthe rate at which sterilant is introduced into chamber 4. In anotherembodiment, a pressure difference between chamber 2 and chamber 4 iscreated with pump 18.

In an alternative embodiment, a pressure differential can be createdbetween the two ends of lumen 42 by applying vacuum to one end of thelumen 42 with vacuum pump 16. In another embodiment, both vacuum pump 16and pump 18 can be operated simultaneously or sequentially to create apressure difference between the two ends of lumen 42. In yet anotherembodiment, both chambers 2 and 4 can be simultaneously be evacuatedwith vacuum pump 16, as long as there is a pressure difference betweenchamber 2 and chamber 4. The sterilant which flows between chamber 2 andchamber 4 through lumen 42 sterilizes the interior of the lumen 42. Thesterilant inside chamber 2 and chamber 4 sterilizes the exterior oflumen device 40.

If the opening 7 includes a material which is permeable to thegermicide, or if the opening 7 fits loosely around the outside of thelumen device 40, the germicide can flow around the outside of the lumendevice 42 in the opening or can penetrate the material which ispermeable to the germicide, thereby contacting and sterilizing thecontact area between the outside of the lumen device and the opening 7in the interface 6 a.

The apparatus of FIG. 8 therefore provides an apparatus and a method forsterilizing the interior and the exterior of the lumen device 40.Placing the lumen device 40 into the opening 7 in the interface 6 aprovides a way to generate a pressure differential between the two endsof the lumen 42 of the lumen device 40 so that sterilant can flowthrough the interior of the lumen 40.

FIG. 9 shows an apparatus similar to the apparatus of FIG. 6A. Theapparatus of FIG. 9 differs from the apparatus of FIG. 6A in that onlycontainer 22 containing lumen device 40 is present in chambers 2 and 4.Container 22 is placed across opening 7 b in the interface 6 c. Lumendevice 40 is then placed across opening 7 d in interface 6 e insidecontainer 22. Container 22 is provided with at least one sterilantvapor-permeable and gas-permeable, but microorganism-impermeablemembrane 24. In FIG. 10, two membranes 24 are present on the ends of thecontainer 22. In other embodiments, the membranes 24 may be placed inother locations of the container 22.

A source of sterilant 12 is located in one or both of containers 10,chamber 2, and/or chamber 4 or any combination thereof. Creating apressure difference between chamber 2 and chamber 4 leads to flow ofsterilant through membrane 24 into container 22, through lumen device 40and through the second membrane 24 into the other chamber. The flow ofsterilant through the lumen device 40 sterilizes the lumen device 40.The container 22 protects the sterility of the lumen device 40, becausethe microorganism-impermeable membranes 24 prevent microorganisms fromentering the interior of the container 22. The sterility of lumen device40 inside container 22 is preserved even if container 22 is removed fromchambers 2 and 4.

In an alternative embodiment, there is only one membrane 24 in thecontainer 22. The container 22 is evacuated and sterilant is flowedthrough the container 22 and through membrane 24 to sterilize the lumendevice 40.

FIG. 10 shows another apparatus similar to the apparatus shown in FIG.4, except that only lumen device 40 is in chambers 2 and 4. Lumen deviceis placed through opening 7 in interface 6 f of chamber 4. The areaaround the opening 7 may be made of a material which is permeable to thegermicide. The germicide can penetrate the material and sterilize ordisinfect the contact area between the interface and the lumen device.

A source of sterilant 12 is present in one or both of chambers 10, oneor both of chambers 2 and 4, or any combination thereof. A pressuredifferential is created between chamber 2 and 4, thereby flowingsterilant between chamber 2 and chamber 4 through the interior of lumendevice 40, thereby sterilizing the interior of the lumen device 40. Thepressure difference can be caused by generating sterilant vapor,evacuating chamber 2 or chamber 4, pumping sterilant between chambers 2and 4 with pump 16, or any combination thereof.

In an exemplary embodiment, chamber 2 is evacuated with the vacuum pump16. Evacuating chamber 2 also evacuates chamber 4 and lumen device 40.An antimicrobial fluid is injected into chamber 2 or is generated from asource of antimicrobial fluid. The source of antimicrobial fluid can bein an enclosure 10 in fluid communication with chamber 2 or in chamber2. Injection of the antimicrobial fluid into chamber 2 creates a higherpressure in chamber 2 than in chamber 4. The antimicrobial fluid flowsfrom chamber 2 into chamber 4 through the lumen device 40 because of thepressure difference between chamber 2 and chamber 4, sterilizinginterior of the lumen device 40. The antimicrobial fluid in chamber 2sterilizes the exterior of the lumen device 40.

Chamber 2 may be evacuated again after sterilant flows through lumendevice 40. Evacuating chamber 2 creates a pressure difference betweenchamber 2 and chamber 4, and the antimicrobial fluid flows from chamber4 into chamber 2 because of the pressure difference. The flow ofantimicrobial fluid from chamber 4 into chamber 2 through the lumendevice 40 after evacuating chamber 2 again enhances the sterilization ofthe lumen device 40.

Alternatively, or in addition, chamber 2 may be vented. Venting chamber2 creates a higher pressure in chamber 2 than in chamber 4, therebydriving antimicrobial fluid from chamber 2 into chamber 4 though lumendevice 40. Venting chamber 2 therefore enhances the sterilization of theinterior of the lumen device 40.

Center chamber 4 can also be evacuated by vacuum pump 16 through theline connected to Valve 15 b. Sterilant may be introduced into chamber 4from a source of sterilant 12 inside chamber 4 or from a source ofsterilant 12 in container 10. Vacuum pump 16 can evacuate both chamber 2and chamber 4 simultaneously.

Opening 7 may contain a material which is permeable to the sterilant,thereby allowing the sterilant to penetrate the contact area between theexterior of the lumen device 40 and the interior of the opening 7,thereby sterilizing the contact area between the lumen device 40 and theopening 7.

FIG. 11 shows a simplified embodiment of the apparatus of FIG. 10. Lumendevice 40 is placed though opening 7 in interface 6 g on chamber 4.Chamber 4 is located inside chamber 2. Chamber 4 and chamber 2 are influid communication with vacuum pump 16. A source of sterilant 12 ispresent in container 10 and/or chamber 2. In an exemplary embodiment,the volume of chamber 4 is larger than the internal volume of lumendevice 40.

Although the apparatus of FIG. 11 can be used in a variety of manners,in an exemplary embodiment, chambers 2 and 4 are evacuated with vacuumpump 16. A source of sterilant 12 is present in container 10. Sterilantis introduced into chamber 2 by opening valve 14 c. The sterilant isdrawn into chamber 4 through the lumen device 40 sterilizing theinterior of lumen device 40. The exterior of the lumen device 40 issterilized with the sterilant in chamber 2 and chamber 4.

Although a variety of sterilants can be used, a source of sterilantcomprising peroxide is an exemplary sterilant. Aqueous hydrogen peroxideis a preferred source of sterilant. A solid source of peroxide is analternative preferred source of sterilant. In an exemplary embodiment,plasma can be generated and contacted with the device to be sterilizedor disinfected. The source of plasma can be inside chamber 2 or chamber4, or the source of plasma can be outside chamber 2 and chamber 4, andplasma can be flowed into chamber 2, chamber 4, or both chamber 2 andchamber 4.

Various modifications and alterations of this invention will be apparentto those skilled in the art without departing from the scope and spiritof this invention. It should be understood that the invention is notlimited to the embodiments disclosed therein, and that the claims shouldbe interpreted as broadly as the prior art allows.

1. A method for sterilizing a lumen device in a vacuum chamber, saidmethod comprising: separating said vacuum chamber into a firstcompartment and a second compartment with an interface, wherein at leastone lumen device extends across said interface, whereby said firstcompartment is in fluid communication with said second compartmentthrough said at least one lumen device; evacuating the vacuum chamber,thereby decreasing the pressure in said first compartment and saidsecond compartment; introducing germicide into at least one of saidfirst compartment and said second compartment, wherein said introducingoccurs after evacuating; and creating a pressure difference between saidfirst compartment and said second compartment, thereby flowing germicidebetween said first compartment and said second compartment through saidat least one lumen device.
 2. The method of claim 1, wherein saidgermicide comprises hydrogen peroxide.
 3. The method of claim 1, whereinsaid interface comprises at least one opening.
 4. The method of claim 3,wherein said at least one opening comprises a material which ispermeable to said germicide, whereby a contact area between saidinterface and said lumen is contacted with germicide.
 5. The method ofclaim 3, further comprising adjusting said at least one opening.
 6. Themethod of claim 1, further comprising increasing a pressure in saidfirst compartment and in said second compartment, wherein saidincreasing is after said introducing and said creating a pressuredifference.